Amanda Bynes' doctors have reportedly recommended ''prolonged treatment''.

The 27-year-old star - who is currently under involuntary psychiatric hold - is showing signs of improvement but it is said medical professionals are keen to keep her in a unit at UCLA until 2014.

A source told ''[Doctor's have] been observing Amanda, and there has been some improvement ... However, her diagnosis is complex, and the appropriate drug cocktail to treat her hasn't been achieved yet.

''Therefore, her treatment team believes Amanda would benefit from prolonged treatment at UCLA, for at least the rest of the year.

''She has her good days and bad days, and the goal is obviously to get her therapeutic and stable before being released.''

The actress' mother Lynn has been granted a temporary conservatorship over her, but reports claim it needs to become ''permanent'' in case Amanda refuses further treatment.

The insider added: ''Lynn needs to be granted permanent conservatorship because Amanda wouldn't agree to continue with treatment.''

A source recently explained the arrangement, insisting all ''important decisions'' with regards to her wealth and well-being still has to pass through her ''lawyer and the judge''.

They said: ''Amanda can't make important decisions regarding her finances and welfare. But her parents can't either. Everything still needs to go through Amanda's lawyer and the judge.